Ricky Gervais received an extra-special gift to mark his 50th birthday - a guitar used in classic comedy This Is Spinal Tap.The British funnyman is close pals with Christopher Guest, who played musician Nigel Tufnel in the 1984 mockumentary about a rock band, and they headed out for a meal to celebrate Gervais reaching the milestone on Saturday (25Jun11). And when Guest and his wife Jamie Lee Curtis handed over a pile of gifts for The Office creator, he was stunned to unwrap a Fender guitar used by Guest in the spoof movie. In a blog post detailing how he spent his big day, Gervais writes, "Worked-out, then we went to my birthday dinner with the lovely Chris and Jamie Guest at Galvin at Windows restaurant (in London). Some more lovely presents and the usual wonderful meal from one of the best restaurants in the world. "But then something quite special happened. Chris gave me his Fender guitar from Spinal Tap. I was speechless. It was really too much. "What a remarkable gift. I had to have a little lie down in his hotel suite."